Unconditionally secure key distillation from multi-photons

In this paper, we prove that the unconditionally secure key can be surprisingly extracted from {\it multi}-photon emission part in the photon polarization-based QKD. One example is shown by explicitly proving that one can indeed generate an unconditionally secure key from Alice's two-photon emission part in ``Quantum cryptography protocols robust against photon number splitting attacks for weak laser pulses implementations'' proposed by V. Scarani {\it et al.,} in Phys. Rev. Lett. {\bf 92}, 057901 (2004), which is called SARG04. This protocol uses the same four states as in BB84 and differs only in the classical post-processing protocol. It is, thus, interesting to see how the classical post-processing of quantum key distribution might qualitatively change its security. We also show that one can generate an unconditionally secure key from the single to the four-photon part in a generalized SARG04 that uses six states. Finally, we also compare the bit error rate threshold of these protocols with the one in BB84 and the original six-state protocol assuming a depolarizing channel.Comment: The title has changed again. We considerably improved our presentation, and furthermore we proposed & analyzed a security of a modified SARG04 protocol, which uses six state

Real-time food intake classification and energy expenditure estimation on a mobile device

© 2015 IEEE.Assessment of food intake has a wide range of applications in public health and life-style related chronic disease management. In this paper, we propose a real-time food recognition platform combined with daily activity and energy expenditure estimation. In the proposed method, food recognition is based on hierarchical classification using multiple visual cues, supported by efficient software implementation suitable for realtime mobile device execution. A Fischer Vector representation together with a set of linear classifiers are used to categorize food intake. Daily energy expenditure estimation is achieved by using the built-in inertial motion sensors of the mobile device. The performance of the vision-based food recognition algorithm is compared to the current state-of-the-art, showing improved accuracy and high computational efficiency suitable for realtime feedback. Detailed user studies have also been performed to demonstrate the practical value of the software environment

On the performance of two protocols: SARG04 and BB84

We compare the performance of BB84 and SARG04, the later of which was proposed by V. Scarani et al., in Phys. Rev. Lett. 92, 057901 (2004). Specifically, in this paper, we investigate SARG04 with two-way classical communications and SARG04 with decoy states. In the first part of the paper, we show that SARG04 with two-way communications can tolerate a higher bit error rate (19.4% for a one-photon source and 6.56% for a two-photon source) than SARG04 with one-way communications (10.95% for a one-photon source and 2.71% for a two-photon source). Also, the upper bounds on the bit error rate for SARG04 with two-way communications are computed in a closed form by considering an individual attack based on a general measurement. In the second part of the paper, we propose employing the idea of decoy states in SARG04 to obtain unconditional security even when realistic devices are used. We compare the performance of SARG04 with decoy states and BB84 with decoy states. We find that the optimal mean-photon number for SARG04 is higher than that of BB84 when the bit error rate is small. Also, we observe that SARG04 does not achieve a longer secure distance and a higher key generation rate than BB84, assuming a typical experimental parameter set.Comment: 48 pages, 10 figures, 1 column, changed Figs. 7 and

FGGE/SMMR-30 tape specification and shipping letter description

The Nimbus-7 FGGE/SMMR-30 tape which contains sea ice concentration data in 30 km resolution which are extracted and reformatted from Nimbus-7 SMMR PARM-30 tapes in accordance with the FGGE level II International Exchange Format Specification is outlined. There are three types of files on a FGGE/SMMR-30 tape. The first file on the tape is a test file. The second file on the tape is a tape header file. The remaining one or more files are data files. All files are terminated with a single end of file (EOP) tape mark. The last file is terminated with two EOF tape marks. All files are made up of one or more physical records. Each physical record contains 2960 bytes. Each data file contains all available values for a 6 hour synoptic time period

FGGE/ERBZ tape specification and shipping letter description

The FGGE/ERBZ tape contains 5 parameters which are extracted and reformatted from the Nimbus-7 ERB Zonal Means Tape. There are three types of files on a FGGE/ERBZ tape: a tape header file, and data files. Physical characteristics, gross format, and file specifications are given. A sample tape check/document printout (shipping letter) is included

FGGE/SBUV tape specification and shipping letter description

The FGGE/SBUV Level 2C data set consists of 12 9-track data tapes, each of which contains total ozone and ozone profile data for one calendar month grouped in files containing the data in a 6 hour synoptic time block. The data flow and quality checks in the production of this data set are described as well as the format of the data tapes and the accompanying shipping documents

FGGE/ERBM tape specification and shipping letter description

The Nimbus-7 FGGE/ERBM tape contains 27 ERB parameters which are extracted and reformatted from the Nimbus-7 ERB-MATRIX tape. There are four types of files on a FGGE/ERBM tape: a test file; tape-header file which describes the data set characteristics and the contents of the tape; a grid-descriptor file which contains the information of the ERB scanning channel target number and their associated latitude limits and longitude intervals; and one or more data files. A single end-of-file (EOF) tape mark is written after each file, and two EOF marks are written after the last data file on the tape

A proposal for founding mistrustful quantum cryptography on coin tossing

A significant branch of classical cryptography deals with the problems which arise when mistrustful parties need to generate, process or exchange information. As Kilian showed a while ago, mistrustful classical cryptography can be founded on a single protocol, oblivious transfer, from which general secure multi-party computations can be built. The scope of mistrustful quantum cryptography is limited by no-go theorems, which rule out, inter alia, unconditionally secure quantum protocols for oblivious transfer or general secure two-party computations. These theorems apply even to protocols which take relativistic signalling constraints into account. The best that can be hoped for, in general, are quantum protocols computationally secure against quantum attack. I describe here a method for building a classically certified bit commitment, and hence every other mistrustful cryptographic task, from a secure coin tossing protocol. No security proof is attempted, but I sketch reasons why these protocols might resist quantum computational attack.Comment: Title altered in deference to Physical Review's fear of question marks. Published version; references update

Theory of the Three-Group Evolutionary Minority Game

Based on the adiabatic theory for the evolutionary minority game (EMG) that we proposed earlier[1], we perform a detail analysis of the EMG limited to three groups of agents. We derive a formula for the critical point of the transition from segregation (into opposing groups) to clustering (towards cautious behaviors). Particular to the three-group EMG, the strategy switching in the "extreme" group does not occur at every losing step and is strongly intermittent. This leads to an correction to the critical value of the number of agents at the transition, $N_c$. Our expression for $N_c$ is in agreement with the results obtained from our numerical simulations.Comment: 4 pages and 2 figure